The present invention relates to a power-driven hand tool having a housing in which a drive for a tool is received, having at least a first handle which is fastened to a support that is attached at a first end to the housing and with a second end stands laterally out from the housing.
A hand tool of this kind is known from DE 38 26 212 A1.
The known hand tool is a hammer drill with a fixed stock handle mounted beneath the housing, and an additional stock handle (chiseling handle) which is mounted only when chiseling. The chiseling handle is attached to the housing on a cross brace provided perpendicular to the stock handle, and extends parallel to the stock handle but in the opposite direction, i.e. upward. In addition, the chiseling handle can be pivoted a certain amount in order to allow the hand tool to be held better.
The known hand tool may indeed allow improved gripping of the hand tool as a hammer drill, but the additional installation and removal of the second handle has proven cumbersome and in some cases disruptive. In addition, even with an additional handle of this kind, an optimal and in particular ergonomic posture for the user of the hand tool is still not possible.
In the case of a power drill, it is moreover known in principle from EP 0 142 650 A2 to provide at the end of the drill, in addition to a pistol-shaped handle, an additional handle which is attached to the spindle neck of the power drill below the drive train housing by means of a band clamp. The additional handle is joined at both of its ends to a yoke which transitions into the band clamp for attachment to the spindle neck of the drill.
Although an improved and more economical posture is made possible in this fashion, greater damping is often desirable, particularly when used for hammer-drilling.
A variety of yoke handle arrangements, some of them adjustable, for use with hand tools has also been disclosed (cf. DE 25 59 132 C2, DE 39 21 752 A1, U.S. Pat. No. 4,060,940). The use of such yoke handles results in some cases in an enlargement, and in cumbersome handling, of the hand tool. Moreover, as before, sufficient damping is not guaranteed with respect to vibrations which occur while working.
A further problem with hand tools of this kind occurs in particular when working with heavy right-angle grinders, which as a rule must be held using two handles, specifically a first handle on the front end of the housing in the vicinity of the grinding disk, and a second handle at the rear end of the housing which is usually combined with a switch. In the case of a right-angle grinder of this kind as known, for example, from U.S. Pat. No. 4,060,940, the front handle facing the grinding disk is yoke-shaped, and extends above the housing to an attachment point on the safety shroud.
An arrangement of this kind can be optimized either for cutting (working in the direction of the cutting disk), or for roughing (working in planar fashion with the surface of the roughing disk). An optimal posture for both roughing and cutting, with simultaneous damping of the handle, is not, however, possible in this case.